AGM Battery sudden death

[Quickstep192]

I have an AGM battery in my car. One day everything was fine, I didn't use the car for two days and when I got in, it was dead, I mean flatline; not even a dome light. Now the battery won't hold a charge. I have several AGMs in various vehicles, but I've never experienced a death. Is it typical for them to die suddenly and tragically?

[Joe Bob]

How old is it and have you tried shocking? Hi-low alternating charging?

[Fast Freddy 944]

It could be a defect. Is it under warrentee? Do you still have a receipt? Now go handle your bizness.

[zedsn]

If no dome light was left on or something similar I presume the battery was old and that is what they do when they go sometimes. No warning no nothing. You can get in and drive your car shut it off and come back out and try to fire up the car only to find a dead battery. Happened to my family years ago.

[T77911S]

check connections make sure they are clean
check volts with a meter
age of battery
you have/had a drain on the battery that killed it.

[jlex]

Was your alternator charging properly? I keep a voltmeter plugged into the cigarette lighter to make sure it's charging okay...

[LUFTKUL]

Voltage spikes can kill a battery too. Jump start the car and then check the voltage to the battery while running. Make sure to have someone rev the engine while reading as my alternator/voltage regulator would spike to 18+ volts when revved.

[sc_rufctr]

All batteries can fail suddenly. Lots of different reasons but the most common is a shock that breaks something inside.

No good news I'm afraid.

IMO AGM style batteries are really over rated. They're more expensive than traditional lead acid and IME they don't seem to last much longer. YMMV

[Joe Bob]

I'm a marine style Yellow Top Optima user. Can survive multiple full discharges w/o damage. Last one lasted 12 years. Build quality isn't the same any more but I use a quality tender as it isn't my DD anymore....

[422flat6]

AGM batteries are great but they're a bit of a different animal than lead acid batteries. AGM batteries do not tolerate a deep discharge very well and if they fall below 10-11V they will act as if they are completely dead and will not accept a charge. This is why it's important to keep it on an AGM-specific battery tender if it's going to sit for any length of time.

Suggest you Google "how to charge discharged AGM battery" or something similar. There's a lot of info out there on this specific problem. The battery almost certainly didn't go bad on you. Most likely it got discharged due to parasitic drain or a dome light left on. Advice on how to save it when this happens is out there, but I've never let mine die so I'm not going to endorse any particular rescue method without first hand experience. Just trying to point you in the right direction.

[michael lang]

I believe sometimes a battery can be saved but most times not. If that were my scenario, I would start looking for a replacement. Before I learned about batteries, I had a real nice Braille battery when I tracked my car and let it go dead while I did my rebuild. Then, when I was ready to put everything back in, it simply would not charge. No matter how long I had it connected or what I did. I even took it in to the shop to have one of the shop chargers try to bring it back to life. Geez I was pissed! Now, if it is more than one day between drives in my car, the battery stays connected to my BatteryTender.

[dad911]

Originally Posted by Quickstep192

I have an AGM battery in my car. One day everything was fine, I didn't use the car for two days and when I got in, it was dead, I mean flatline; not even a dome light. Now the battery won't hold a charge. I have several AGMs in various vehicles, but I've never experienced a death. Is it typical for them to die suddenly and tragically?

Optima?

The old ones were great, the newer ones not.

[Tremelune]

You might be able to bring it back to life by "forcing" power into it, either by jumping the car and driving, or by attaching a charger in "supply" mode. After that, any tender might be able to bring it back to a good place.

The benefits of AGM are no maintenance and no leakage. Battery life is determined by how it is used and taken care of more than anything else.

[adias]

I use Optimas but if I do not drive the car for more than a few days the Optima is connected to a CTek maintainer. As long as the battery maintains 80% of its capacity it will be fine. As said above, AGM are used to avoid venting issues.